We, using an effective Lagrangian approach, investigated the dipionic transition of the $Y(4500)$ newly well established in the process $e^{+}{e}^{-}\to K^{+}{K}^{-}J/\psi$. In this study, the $Y(4500)$ was considered as a mixture of the $\psi (5S)$ and $\psi (4{{}^{3}D}_1)$, and its dipionic decay to the $J/\psi$ was assumed to occur via charmed meson loops including box and two kinds of triangle loops. The calculated invariant mass spectra due to the different loop mechanisms exhibit distinct differences. These spectrum patterns are found to be nearly independent of the cutoff parameter, especially for the box and $\mathcal{R}$ loops. By means of comparing our calculated results with the future experimental measurements of the ${\pi }^{+}{\pi }^{-}$ and ${\pi }^{\pm }J/\psi$ invariant mass distributions, we could judge which loop mechanism is of more importance in this dipionic transition. The interference among the different kinds of loops is also exhibited. Despite the unknown phase angles between different kinds of loop diagrams, the partial decay width for the process $Y(4500)\to {\pi }^{+}{\pi }^{-}J/\psi$ is estimated to be 250–700 keV, aligning with the estimation obtained by combining BESIII Collaboration measurements and theoretical predictions for $Y(4500)\to K^{+}{K}^{-}J/\psi$. We hope that the present calculations would be tested by the future BESIII or Belle II experiments.

The NUCLEUS experiment aims to detect coherent elastic neutrino-nucleus scattering of reactor antineutrinos on ${\mathrm{CaWO}}_4$ targets in the fully coherent regime, using gram-scale cryogenic calorimeters. The experimental apparatus will be installed at the Chooz nuclear power plant in France, in the vicinity of two $4.25{\mathrm{GW}}_{\mathrm{th}}$ reactor cores. This work presents results from the commissioning of an essential version of the experiment at the shallow Underground Laboratory of the Technical University of Munich. For the first time, two cryogenic target detectors were tested alongside active and passive shielding systems. Over a period of two months, all detector subsystems were operated with stable performance. Background measurements were conducted, providing important benchmarks for the modeling of background sources at the reactor site. Finally, we present ongoing efforts to upgrade the detector systems in preparation for a technical run at Chooz in 2026, and highlight the remaining challenges to achieving neutrino detection.

Intensity interferometry—the correlation of spatially separated light intensities—has historically been an important tool for precision optical astronomical observations. However, due to the extremely narrow field of view and weak signal, its scope has been limited to studies of the morphology of very bright emission regions, such as determinations of angular diameters of nearby hot stars. We propose adding to the detector optics an adjustable path extension that creates a primary interference fringe for widely separated sources, allowing maximum source separations parametrically larger than the angular resolution. This extended-path intensity correlator (EPIC), augmented with advances in single-photon detectors and spectroscopic gratings that improve the signal-to-noise ratio, would enable ground-based astrometry at microarcsecond-level precision in a field of view as large as several arcseconds. EPIC has the potential to revolutionize astrophysical and cosmological observations requiring high-precision differential astrometry on sources of high surface brightness. We outline how EPIC can be employed to detect the astrometric wobble of Earth-like planets around Sun-like stars at tens to hundreds of parsecs and expect that EPIC’s larger field of view will expand the power of intensity interferometry to a broad range of astronomical applications.

We study nonperturbatively the entanglement generation between two and three emitters in an exactly solvable relativistic variant of the spin-boson model, equivalent to the time-independent formulation of the Unruh-DeWitt detector model. We show that (i) (highly) entangled states of the two emitters require interactions very deep into the light cone, (ii) the mass of the field can generically improve the entanglement generation, (iii) while it is possible to find regimes with genuine Greenberger–Horne–Zeilinger-like tripartite entanglement, it is difficult find regimes where tripartite entanglement can be easily shown to be significant or classified. Result (iii), in particular, suggests that probing the multipartite entanglement of a relativistic quantum field nonperturbatively requires either different probe-based techniques or variants of the Unruh-DeWitt model. Along the way, we provide the regularity conditions for the $N$-emitter model to have well-defined ground states in the Fock space.

It is well-known that quantum groups are relevant to describe the quantum regime of 3D gravity. They encode a deformation of the gauge symmetries parametrized by the value of the cosmological constant. They appear as a form of regularization either through the quantization of the Chern-Simons formulation or the state sum approach of Turaev-Viro. Such deformations are perplexing from a continuum and classical picture since the action is defined in terms of undeformed gauge invariance. We present here a novel way to derive from first principles and from the classical action such quantum group deformation. The argument relies on two main steps. First we perform a canonical transformation, which deforms the gauge invariance and the boundary symmetries, and makes them depend on the cosmological constant. Second we implement a discretization procedure relying on a truncation of the degrees of freedom from the continuum.

This paper presents a derivation of a first-order reduction and $3+1$ decomposition of the teleparallel equivalent of general relativity (TEGR) in the pure-tetrad formulation (no spin connection). Our analysis demonstrates that, in vacuum spacetimes, our $3+1$ TEGR equations have the principal part of the differential operator equivalent to the one of tetrad reformulation of general relativity by Estabrook, Robinson, Wahlquist, and Buchman and Bardeen, and therefore, the presented $3+1$ decomposition of TEGR also admits a symmetric hyperbolic formulation, a desirable property for ensuring well-posedness of the initial value problem. Furthermore, the structure of the $3+1$ equations possesses a lot of similarities with the equations of relativistic electrodynamics and the recently proposed dGREM tetrad-reformulation of general relativity.

Line intensity mapping (LIM) is emerging as a powerful probe of the high-redshift Universe, with a growing number of LIM experiments targeting various spectral lines deep into the epochs of reionization and cosmic dawn. A key remaining challenge is the consistent and efficient modeling of the diverse emission lines and of the observables of different surveys. Here, we present olimpus, a fully analytical effective model to study LIM auto- and cross-power spectra. Our work builds on the 21-cm effective model presented in zeus21, applying it to star-forming lines and improving it in different aspects. Our code accounts for shot noise and linear redshift-space distortions and it includes by default prescriptions for OII, OIII, $\mathrm{H}\alpha$, $\mathrm{H}\beta$, CII, CO line luminosities, together with the 21-cm model inherited from zeus21. Beyond auto- and cross-power spectra, olimpus can produce mock coeval boxes and light cones, and with a computational time of $\sim s$ it is ideal for parameter-space exploration and inference. Its modular implementation makes it easy to customize and extend, enabling various applications, such as Markov chain Monte Carlo analyses and consistent multiline cross-correlations.

Precise initial conditions (ICs) are crucial for accurate computation in cosmological perturbation theory. We derive the consistent ICs for Horndeski theory in the effective field theory (EFT) approach, assuming constant EFT functions at early times. We implement the ICs into the public Boltzmann code eftcamb, and demonstrate that the expected early-time behavior of perturbations and Weyl potential can be obtained with theory-consistent modified gravity (MG) ICs. We identify significant deviations when comparing cosmic microwave background angular power spectra in MG models obtained with consistent MG ICs versus inconsistent GR ICs. Our findings underline the importance of using accurate, theory-consistent MG ICs to ensure robust cosmological constraints on early MG models.

We develop in detail a recently proposed optical-path modification of astronomical intensity interferometers. Extended-path intensity correlation (EPIC, see companion paper) introduces a tunable path extension, enabling differential astrometry of multiple compact sources such as stars and quasars at separations of up to a few arcseconds. Combined with other recent technological advances in spectroscopy and fast single-photon detection, a ground-based intensity interferometer array can achieve microarcsecond resolution and even better light-centroiding accuracy on bright sources of magnitude $m\lesssim 15$. We lay out the theory and technical requirements of EPIC, and discuss the scientific potential. Promising applications include astrometric lensing of stars and quasar images, binary-orbit characterization, exoplanet detection, Galactic acceleration measurements and calibration of the cosmic distance ladder. The introduction of the path extension thus significantly increases the scope of intensity interferometry while reaching unprecedented levels of relative astrometric precision.

We investigate the distribution of an interacting axionlike massive field within a magnetized neutron star. For this we consider the effect of an intense density-dependent axially symmetric stellar magnetic field $\mathbf{B}(r,\theta )$ adding another much weaker, but nonvanishing, electric field. We particularize the latter for the case when a finite chiral charge density is present. The axion field is thus coupled to a generic function $Q(F_0,G_0)$ depending on Lorentz invariants $F_0$, $G_0$ which can be constructed from these electromagnetic fields. From this, the static axion field equations are solved as function of stellar radial coordinate and angular direction, $a(r,\theta )$, using a prescribed linear form for $Q$. In addition, we use a semianalytical approach to calculate the stellar structure in this hybrid system where pressure components are treated under a perturbative scheme, provided induced deformations with respect to spherical symmetry are tiny. Our results show that the axion couplings to magnetic and electric fields along with its mass, critically determine the axion spatial distribution. Furthermore, we focus on the possibility that the axion field might accumulate in specific outer regions of the star, particularly within the crust, where it could form a condensate. We explore the possible presence of magnetic flux tubes from superconductor phases in this outer layer and qualitatively show they may enhance local conversion into photons. We explore prospects of detectability through indirect methods.

The air shower array Carpet-3 detected a 300 TeV photon from the direction of GRB 221009A at 4536 s after the Fermi Gamma-ray Burst Monitor trigger for this event. If the association with this gamma-ray burst is real, then it poses two puzzles. First, why was this photon not absorbed by the extragalactic background light? “New physics” beyond the Standard Model is required to explain how it managed to reach Earth from a cosmological distance. Second, why was this photon detected when the very high energy (VHE) afterglow observed by the Large High Altitude Air Shower Observatory (LHAASO) already faded? A novel astrophysical mechanism is required to explain this delay. In this work we show that Lorentz invariance violation (LIV), which arises as a low-energy limit of certain quantum gravity theories, can solve both puzzles. It shifts thresholds of particle interaction and changes the opacity of the extragalactic background, and causes energy-dependent variations of the photon velocity, which changes the photon time of flight. We investigate the LIV parameter space assuming that the 300 TeV photon is a part of the VHE afterglow detected by the LHAASO in the TeV range. We identify viable solutions and place stringent two-sided constraints on the LIV energy scale required to resolve the observational puzzles. First-order LIV appears to be incompatible with the constraints set by analyzing the TeV afterglow of this gamma-ray burst. Viable solutions emerge for higher orders. In particular, the commonly studied second-order subluminal LIV with $E_{\mathrm{LIV}2}=1.30_{-0.35}^{+0.56}\times {10}^{-7}{E}_{\mathrm{Pl}}$ (95.4% credibility level; $E_{\mathrm{Pl}}$ is the Planck energy) is consistent with all the observed data.

We suggest a systematic calculational scheme for heat kernels of covariant nonminimal operators in causal theories whose characteristic surfaces are null with respect to a generic metric. The calculational formalism is based on a pseudodifferential operator calculus that allows one to build a linear operator map from the heat kernel of the minimal operator to the nonminimal one. This map is realized as a local expansion in powers of spacetime curvature, dimensional background fields, and their covariant derivatives with the coefficients—the functions of the Synge world function and its derivatives. Finiteness of these functions, determined by multiple proper time integrals, is achieved by a special subtraction procedure, which is an important part of the calculational scheme. We illustrate this technique on the examples of the vector Proca model and the vector field operator with a nondegenerate principal symbol. We also discuss smoothness properties of heat kernels of nonminimal operators in connection with the nondegenerate nature of their operator symbols.

In this study, we propose the interpretation of a 650 GeV excess observed at the Large Hadron Collider (LHC) by the CMS Collaboration in terms of the production of a $CP$-odd (or pseudoscalar) Higgs boson $A$, with mass around 650 GeV, decaying into the Standard Model (SM)-like Higgs state $h_{125}$ (in turn decaying into $\gamma \gamma$) and a $Z$ boson (in turn decaying into $b\overline{b}$), within a three-Higgs doublet model (3HDM) featuring two active and one inert doublet, known as the $\mathrm{I}(1+2)\mathrm{HDM}$. This theoretical structure features a spectrum with both the SM-like Higgs boson (with a 125 GeV mass) and a lighter $CP$-even (or scalar) Higgs state with mass around 95 GeV, $h_{95}$, which is present in this scenario for the purpose of simultaneously explaining anomalies seen in the $b\overline{b}$, $\gamma \gamma$, and ${\tau }^{+}{\tau }^{-}$ final states in searches for additional light Higgs states at the Large Electron-Positron collider and LHC itself. It should be noted that, in the $\mathrm{I}(1+2)\mathrm{HDM}$, the inert sector presents loop-induced enhancements to the $h_{95}\to \gamma \gamma$ width via additional scalar charged states, providing a viable mechanism to explain, in particular, the observed (and most significant) diphoton excess at 95 GeV. Taking into account both experimental and theoretical constraints, our results can not only explain the aforementioned anomalies (possibly, aside from the ${\tau }^{+}{\tau }^{-}$, which is the most marginal one) but also predict, as collateral signals, resonant production of the same $CP$-odd scalar $A$ followed by the decays: (i) $A\to h_{95}Z$, leading to the same $\gamma \gamma b\overline{b}$ final state displaying the original 650 GeV anomaly and (ii) $A\to t\overline{t}$, leading to a well-known and studied signature. Both of these signals are potentially explorable at Run 3 of the LHC and most possibly so at the High-Luminosity LHC, while being consistent with current data at a significance level of $2.5\sigma$.

We use a hybrid deep neural network (HDNN) to identify a boosted dark photon jet as a signature of a heavy vectorlike fermionic portal matter (PM) connecting the visible and the dark sectors. In this work, the fermionic PM, which mixes only with the Standard Model (SM) third-generation up-type quark, predominantly decays into a top quark and a dark photon pair. The dark photon then promptly decays to a pair of standard model fermions via the gauge kinetic mixing. We have analyzed two different final states, namely, (i) exactly one tagged dark photon and exactly one tagged top quark jet, and (ii) at least two tagged dark photons and at least one tagged top quark jet at the 13 and 14 TeV LHC center of mass energies. Both these final states receive significant contributions from the pair and single production processes of the top partner. The rich event topology of the signal processes, i.e., the presence of a boosted dark photon and top quark jet pair, along with the fact that the invariant mass of the system corresponds to the mass of the top partner, help us to significantly suppress potential SM backgrounds. We have shown that one can set a $2\sigma$ exclusion limit of $\sim 2.3\mathrm{TeV}$ on the top partner mass with $\sin {\theta }_L=0.1$ and assuming 100% branching ratio of the top partner in the final state with exactly one tagged dark photon and exactly one tagged top quark jet at the 14 TeV LHC center of mass energy assuming $300{\mathrm{fb}}^{-1}$ of integrated luminosity.

Rates for particle interaction processes and decays will be modified in a Lorentz-violating quantum field theory, because of changes to the particle kinematics—particularly through the modified dispersion relations affecting the outgoing particle phase space. We outline here these changes to the rates for three-particle decays. Considering a process with a constant scattering amplitude (not directly modified by the Lorentz violation), we calculate leading order corrections to the kinematics for a decay into three identical spinless particles whose propagation is affected by a $c_{\mu \nu }$-type symmetric tensor background. We examine the angular distribution of the daughter particles and describe the shape of the corresponding Dalitz plot outlining the kinematically allowed region, according to two toy models for the $c_{\mu \nu }$ textures. Precision measurements of the boundaries of this region could be used to constrain Lorentz violation coefficients for the particles involved in processes such as $\eta \to 3{\pi }^0$.

The recent result of the Fermilab Muon g-2 experiment is still in conflict with the standard model (SM) prediction if dispersive methods are used as input for the hadronic vacuum polarization. We seek models where the same set of mediators around the weak scale or above contribute to neutrino masses and to the muon $g-2$ through a chiral enhanced contribution. As family lepton number violation is inherent to the former, non-negligible charged lepton flavor violation will be induced. We arrive at the following field content additional to the SM: one Higgs doublet, one singly charged scalar, and one right-handed neutrino. Neutrino masses will be generated by a combination of mechanisms: the tree-level seesaw, Zee mechanism, and Grimus-Neufeld mechanism, while lepton flavor violation will be minimized by considering Yukawa-aligned Higgs doublets. The setting is flexible enough to account for $(g-2{)}_{\mu }$, the Cabibbo angle anomaly, and the $W$ mass deviation, while avoiding dangerous charged lepton flavor violation.

We derive a Landau field theory for a lattice higher gauge theory defined on $p$-dimensional open cells (i.e., sites, links, faces, cubes, etc.), and study its continuum-limit and phases. In this approach, the $p$-dimensional Wilson-surface operator of the higher gauge theory is promoted to a fundamental functional field that is charged under the $p$-form global symmetry. By explicitly solving the functional equation of motion, we show that the classical solution exhibits the area (perimeter) law in the strong (weak) gauge coupling limit. In the deconfined phase, we also construct topological defects for both U(1) and ${\mathbb{Z}}_N$ higher-form gauge theories, as analogs of vortex and domain-wall solutions in conventional field theories with 0-form global symmetries. Besides, we examine low-energy effective theory by identifying the phase modulations of the functional field as low-energy modes, and discuss the Coleman-Mermin-Wagner theorem for higher-form global symmetries. Finally, we discuss infrared duality among Landau field theories, which originates from Kramers-Wannier duality in lattice higher-form gauge theories.

Hidden-charm decays provide irreplaceable platforms for probing the structures of charmoniumlike states, such as $X(3872)$, $Y(4260)$, and $Z_c(3900)$, and their heavy-quark-symmetry partners. In the hadronic molecular scenario, these hidden-charm decays are dominated by intermediate meson loops (IMLs), and the couplings of ${\chi }_{cJ}\to D^{(*)}{\overline{D}}^{(*)}$ are essential building blocks of the amplitudes for the pionic and radiative transitions of the charmoniumlike states to the ${\chi }_{cJ}$ and $h_c$ states, e.g., $X(3872)\to {\pi }^0{\chi }_{cJ},\pi \pi {\chi }_{cJ},\gamma {\chi }_{cJ}$, and $Y(4260)\to {\pi }^0{h}_c,\eta h_c$. These couplings cannot be extracted from the partial decay widths of the ${\chi }_{cJ}$ directly and only have estimated values from the vector meson dominance (VMD) model. Utilizing the recent precise determination of the pole position and the isospin breaking properties of the $X(3872)$, we give an estimation on the upper bounds of the absolute values of the ${\chi }_{cJ}\to D^{(*)}{\overline{D}}^{(*)}$ couplings. Our results show that the VMD model may overestimate the ${\chi }_{cJ}\to D^{(*)}{\overline{D}}^{(*)}$ couplings considering the $X(3872)$ as a $D{\overline{D}}^{*}$ hadronic molecule with a binding energy about tens of keV. These upper limits can be used and tested in other hidden-charm transitions of the charmoniumlike states to the ${\chi }_{cJ}$ and $h_c$.

In this work, we study the properties of single-flavor heavy baryons, ${\mathrm{\Omega }}_{\mathrm{ccc}}$ and ${\mathrm{\Omega }}_{\mathrm{bbb}}$, in a strong magnetic field. For that sake, we simply treat the baryons as quark–diquark two-body systems, and a systematic formalism is developed to deal with two-body Schrödinger equations in a magnetic field. It is found that (1) The orbital properties of ${\mathrm{\Omega }}_{\mathrm{bbb}}$ are almost not affected by the magnetic field, (2) ${\mathrm{\Omega }}_{\mathrm{ccc}}$ is more tightly bound in the presence of a magnetic field, and (3) the magnetic-spin effect dominates over the magnetic-orbital effect. Applying to peripheral heavy ion collisions, ${\mathrm{\Omega }}_{\mathrm{ccc}}$ is much better than ${\mathrm{\Omega }}_{\mathrm{bbb}}$ to explore the magnetic effect, and the discovery of ${\mathrm{\Omega }}_{\mathrm{ccc}}$ could be more promising.

Analytic results for the next-to-leading order electroweak radiative corrections to the decay of the polarized $W$ boson into a pair of heavy quarks are presented. Finite fermion masses are taken into account throughout this calculation, and in performing the collinear limit for the final quark states and all light fermions taking part in this process, the importance of mass effects is demonstrated. This gives hints for the deviation of the total decay rate and the branching ratios into massive fermions between experimental measurements and theoretical predictions.